He attended Palm Beach Currumbin High School on the Gold Coast during his teenage years and was classmates with future professional surfers Mick Fanning and Joel Parkinson.

[3] Smeltz lives in Sydney with his wife Nikki (who later became a federal election candidate for United Australia Party) and daughters Bonnie and Scarlett but spends the off season on the Gold Coast and still considers it to be his home.

[8] In November 2008 the Phoenix lost its battle to retain Smeltz for the 2009 season as he signed a three-year deal with A-League expansion club Gold Coast United.

[9] Smeltz scored nine goals on his Gold Coast United debut as Miron Bleiberg's men recorded a 12–1 victory in their inaugural outing, a friendly against Mudgeeraba SC.

On 12 July 2010, after a stellar season with Gold Coast United, it was announced Smeltz had agreed to terms with Chinese club Shandong Luneng on a two-year contract subject to passing a medical.

Shandong Luneng had paid the transfer fee to Gold Coast United, but a Football Federation Australia source confirmed that Gold Coast United had not dispatched Smeltz's International Transfer Clearance form, meaning Smeltz was therefore free to rejoin them without any possibility of an international tug-of-war over his services.

On 17 July 2010, Gold Coast United owner Clive Palmer publicly stated that he is "hopeful of retaining him for the coming season."

On 20 March 2011 it was announced that Perth Glory and Smeltz signed a three-year contract worth A$4.1 million with the A-League club as a marquee.

On 18 May 2014, it was announced that Smeltz would be parting ways with Perth Glory after three years at the club, to join Sydney FC on a one-year deal.

On 19 November 2007, following his impressive form with Wellington Phoenix in the A-League and consistent performances for the All Whites, Smeltz was voted New Zealand footballer of the year, ahead of FA Premier League star Ryan Nelsen and Celtic striker Chris Killen.

[28] During a World Cup qualifying match against New Caledonia on 22 March 2013, Smeltz was the victim of a high boot to the face in the opposing penalty area, leaving him bloodied.

[31] Napier City Rovers MetroStars AFC Wimbledon Perth Glory Sydney FC Kedah FA New Zealand Individual